Technical Field
The present invention relates to modified and functionalized gold nanoparticles. More particularly, the present invention relates to gold nanoparticles coated with Schiff-base function groups. The present invention includes the use of the gold nanoparticles as fluorescent probes for chemical sensing of metal ions such as Fe(III).
Description of the Related Art
The “background” description provided herein is for the purpose of generally presenting the context of the disclosure. Work of the presently named inventors, to the extent it is described in this background section, as well as aspects of the description which may not otherwise qualify as prior art at the time of filing, are neither expressly or impliedly admitted as prior art against the present invention.
Iron with its chemical versatility is essential for the proper functioning of numerous organisms in the entire spectrum of biological system. In human body, iron is one of the most essential trace elements; deficiency of ferric ion (Fe (III)) in the body causes anemia, hemochromatosis, liver damage, diabetes, Parkinson's disease and cancer [B. D'Autreáux, N. P. Tucker, R. Dixon and S. A. Spiro, Nature 2005, 437, 769-772; Y. Xing and A. Ton, Org. Lett 2006, 8, 1549; G. E. Tumambac, C. M. Rosencrance and C. Wolf, Tetrahedron 2004, 60, 11293; S. Narayanaswamy, T. Govindaraju, Sens. Actuators B 2012, 161, 304—each incorporated herein by reference in its entirety]. Fe(III) also plays crucial role in the growth and development of living cells and catalyze numerous biochemicals processes [J. W. Lee and J. D. Helmann. Nature 2006, 440, 363-367—incorporated herein by reference in its entirety]. On the other hand, the physiological abundance of Fe(III) causes imbalance, thereby triggering multiple organ (heart, pancreas, and liver) failure [E. D. Weinberg, Eur J Cancer Prev 1996, 5, 19-36; Z. Li, Y. Zhou, K. Yin, Z. Yu, Y. Li, J. Ren, Dyes and Pigments 2014 105, 7-11—each incorporated herein by reference in its entirety]. Therefore, detection of Fe(III) in trace levels is of great relevance. In this regard, judicious selection and proper design of an adequate receptor is vital. Recently, a number of studies on the development of Schiff-base based chemosensors for the detection of Hg(II), Zn(II), Al(III) and other ions have been reported in literature [S. A. Lee, G. R. You, Y. W. Choi, H. Y. Jo, A. R. Kim, I. Noh, S.-J. Kim, Y. Kim, and C. Kim, Dalton Trans., 2014, 43, 6650-6659; Y. Zhou, H. N. Kim, J. Yoon, Bioorg. Med. Chem. Lett. 2010, 20, 125-128; Z. Dong, X. Tian, Y. Chen, Y. Guo, J. Ma, RSC Adv. 2013, 3, 1082-1088—each incorporated herein by reference in its entirety]. However, the availability of chemosensors for Fe(III) with high detection threshold is rather limited.
Conventional Fe(III) detection and analytical techniques include, for example, coupled-plasma atomic emission spectrometry (ICP-AES), inductively coupled plasma mass spectrometry (ICPMS), atomic absorption spectrometry (AAS) and voltammetry [K. Pomazal, C. Prohaska, I. Steffan, G. Reich, J. F. K. Huber, Analyst, 1999, 124, 657; M. E. C. Busto, M. M. Bayon, E. B. Gonzalez, J. Meija, A. S. Medel, Anal. Chem., 2005, 77, 5615; G. L. Arnold, S. Weyer, A. D. Anbar, Anal. Chem., 2004, 76, 322; J. E. T. Andersen, Analyst, 2005, 130, 385; C. M. G. van den Berg, Anal. Chem., 2006, 78, 156—each incorporated herein by reference in its entirety]. However, these methods are expensive, bulky and time consuming, as they require tedious pretreatment procedures for sample preparation. Fluorescent microscopy based on optical fluorescence on the other hand, is a simple and easy, low cost and highly selective tool for studying localization, trafficking and expression levels of biomolecules and metal ions within living cells [O. Tour, S. Adams, R. Kerr, R. Meijer, T. Sejnowski, R. Tsien, R. Y. Tsien, Nat. Chem. Biol., 2007, 3, 423-431; (b) M. Hangauer, C. Bertozzi, Angew. Chem., Int. Ed., 2008, 47, 2394-2397—incorporated herein by reference in its entirety]. To date, most of the Fe(III) sensing is based either on the fluorescence quenching mechanism because of the paramagnetic nature of ferric iron, or on the “turn on” mechanism [J. L. Bricks, A. Kovalchuk, C. Trieflinger, M. Nofz, M. Buschel, A. I. Tolmachev, J. Daub, K. Rurack, J. Am. Chem. Soc. 127 (2005) 13522-13529; J. P. Sumner, R. Kopelman, Analyst 130 (2005) 528-533; M. Y. She, Z. Yang, B. Yin, J. Zhang, J. Gu, W. T. Yin, J. L. Li, G. F. Zhao, Z. Shi, Dyes Pigments 92 (2012) 1337-1343; S. R. Liu, S. P. Wu, Sensor. Actuat. B-Chem. 171 (2012) 1110-1116; M.-R. Huang, S.-J. Huang, X.-G. Li, J. Phys. Chem. C 115 (2011) 5301-5315—each incorporated herein by reference in its entirety].
Merging nanotechnology with the signaling unit can lead to the formation of unique materials, thereby enabling the development of a suite of highly efficient chemosensors for their niche applications in drug delivery, imaging, catalysis, chemical and biochemical sensing [M. N. Shaikh, H.-K. Kim, J-A. Park, Y. Chang and T.-J. Kim, Bull. Korean Chem. Soc. 2010, 31, 1177-1181; C. Alric, J. Taleb, G. L. Duc, C. Mandon, C. Bilotey, A. L. Meur-Herland, T. Brochard, F. Vocanson, M. Janier, P. Perriat, S. Roux and O. Tillement, J. Am. Chem. Soc. 2008, 130, 5908; R. Abu-Reziq, H. Alper, D. Wang and Michael L. Post, J. Am. Chem. Soc. 2006, 128, 5279-5282; J.-J. Lin, J.-S. Chen, S.-J. Huang, J.-H. Ko, Y.-M. Wang, T,-L. Chen, L.-F. Wang, Biomaterials 2009, 30, 5114-5124; L. Bai, L. Zhu, C. Y. Ang, X. Li, S. Wu, Y. Zeng, H. Agren and Y. Zhao, Chem. Eur. J. 2014, 20, 4032-4037—each incorporated herein by reference in its entirety]. Gold nanoparticles (AuNPs), for example, have found applications, on the basis of their size- and shape-controlled synthesis, ease of functionalization and facile surface modification with diverse ligands. In this context, considerable effort has been made for developing AuNPs as excellent probes for cations [S.-P. Wu, Y.-P. Chen, Y.-M. Sung, Analyst 2011, 136, 1887-1891; Y. Kim, R. C. Johnson, J. T. Hupp, Nano Lett. 1 (2001) 165-167; Y. Xue, H. Zhao, Z. Wu, X. Li, Y. He, Z. Yuan, Analyst 136 (2011) 3725-3730; J. Yin, T. Wu, J. Song, Q. Zhang, S. Liu, R. Xu, H. Duan, Chem. Mater. 23 (2011) 4756-4764; A.-J. Wang, H. Guo, M. Zhang, D.-L. Zhou, R.-Z. Wang, J.-J. Feng, Microchim. Acta180 (2013) 1051-1057; V. V. Kumar, S. P. Anthony, Sens. Actuators B 191 (2014) 31-36; S. K. Tripathy, J. Y. Woo, C. Han, Sens. Actuators B 181 (2013) 114-118; Y. Chen, I. Lee, Y. Sung, S. Wu, Sens. Actuators B 188 (2013) 354-359; D. Maity, R. Gupta, R. Gunupuru, D. N. Srivastava, P. Paul, Sens. Actuators B 191 (2014) 757-764—each incorporated herein by reference in its entirety], anions [K. S. Youk, K. M. Kim, A. Chatterjee, K. H. Aim, Tetrahedron Lett. 49 (2008) 3652-3655; W. L. Daniel, M. S. Han, J. S. Lee, C. A. Mirkin, J. Am. Chem. Soc. 131 (2009) 6362-6363; L. Chen, W. Lu, X. Wang, L. Chen, Sens. Actuators B 182 (2013) 482-488; H. Deng, C. Wu, A. Liu, G. Li, W. Chen, X. Lin, Sens. ActuatorsB 191 (2014) 479-484—each incorporated herein by reference in its entirety], small molecules [Z. Sun, Z. Cui, H. Li, Sens. Actuators B 183 (2013) 297-302—incorporated herein by reference in its entirety], proteins [C. S. Tsai, T. B. Yu, C. T. Chen, Chem. Commun. 427 (2005) 4273-4275; A. Laromaine, L. Koh, M. Murugesan, R. V. Ulijn, M. M. Stevens, J. Am. Chem. Soc. 129 (2007) 4156-4157—each incorporated herein by reference in its entirety], nucleic acids [H. Li, L. Rothberg, Proc. Natl. Acad. Sci. U.S.A. 101 (2004) 14036-14039; C. A. Mirkin, R. L. Letsinger, R. C. Mucic, J. J. Storhoff, Nature 382 (1996) 607-609—each incorporated herein by reference in its entirety], and, other analytes. Recently, Bai et al. have reported 4-piperazinyl-1,8-naphthalimide functionalized AuNPs for Fe(III) recognition via interparticle aggregation. AuNPs can be modified by capping agents, possess excellent optical properties such as high extinction coefficients, and distance-dependent plasmonic absorption [M.-C. Daniel, D. Astruc, Chem. Rev. 104 (2004) 293-346; C. Burda, X. Chen, R. Narayanan, M. A. El-Sayed, Chem. Rev. 105 (2005) 1025-1102—each incorporated herein by reference in its entirety]. This has led to the development of functionalized AuNPs for application as colorimetric probes. Notably, they have received great attention in visual sensing because of measurable plasmonic absorbance shift [A. Majzik, L. Fülöp, E. Csapó, D. Seb″ok, T. Martinek, F. Bogár, B. Penke, Imre Dékány, Colloids Surf. B 81 (2010) 235-241; E. Csapó, R. Patakfalvi, V. Hornok, Á. Sipos, A. Szalai, M. Csete, I. Dékány, Colloids Surf. B 98 (2012) 43-49; A. Szalai, Á. Sipos, E. Csapó, L. Tóth, M. Csete, I. Dékány, Plasmonics 8 (2013) 53-62—each incorporated herein by reference in its entirety].
In contrast to the availability of such diverse chemosensors, organic ligand coated AuNP based sensors, such as DNA aptamer functionalized AuNPs [Tan D., He Y., Xing X., Zhao Y., Tang H., Pang D., Talanta. 113 (2013) 26-30—incorporated herein by reference in its entirety], have not been as frequently explored.
In view of the foregoing, one object of the present disclosure is to provide gold nanoparticle-based chemosensors with high selectivity and high detection threshold for metal ions such as Fe(III).